A three-dimensional measuring machine suitable for measuring a work including both of a measurement area which requires high precision and a measurement area which may be measured with relatively low precision within the surface shape of a work is known (refer to Patent Literature 1). The Patent Literature 1 shows a combination of a bridge-type CNC three-dimensional coordinate measuring machine and a measuring head provided to be movable in three directions of the measuring machine by the measuring machine.
The bridge-type three-dimensional measuring machine generally comprises a base, an X-axis table provided to be movable on the upper face of the base in a horizontal direction, a column erected on the base, a beam supported by the column, a Y-axis slider provided to be movable along the beam, a Z-axis slider provided to be liftable along a guide of the Y-axis slider, and a spindle connected to the Z-axis slider. Patent Literature 1 is characterized in that a measuring head is mounted at the tip of the spindle. As shown in FIG. 7, the measuring head 1 comprises a Z-axis slide mechanism 2 detachably provided at the tip of a spindle of the three-dimensional measuring machine, a Y-axis slide mechanism 3 supported by the Z-axis slide mechanism 2 to be movable in Z-axis direction, an X-axis slide mechanism 4 supported to be movable by the Y-axis slide mechanism 3 in Y-axis direction, and a probe 5 supported to be movable by the X-axis slide mechanism 4 in the X-axis direction.
According to Patent Literature 1, the drive mechanisms 2, 3 and 4 of the measuring head 1 moves the probe 5, so that a highly precise measurement is performed in a small measurement area. Further, the drive mechanism of the three-dimensional measuring machine moves the measuring head 1, so that a measurement of low to medium level precision is smoothly performed in a large measurement area.